This invention relates to a burner in which a liquid fuel, such as oil, is first gasified, mixed with air, and then burned. Gasification occurs by mixing the fuel with hot burner gases coming from the burner chamber.
Burners using gasified fuel are not new, although the techniques for gasification, and the success of the techniques, has varied.
Gasification systems are shown in U.S. Pat. Nos. 2,197,347, and 3,308,868 where a portion of the oil is burned and used to gasify the remainder; U.S. Pat. Nos. 2,735,481 and 3,320,743 where the fuel is gasified by being mixed with heated air; and U.S. Pat. No. 3,361,183, where gasification is obtained by recirculating a portion of the combustion gases into admixture with the fuel and a Venturi is used to draw in the gasified fuel and the hot combustion gases. In addition, multiple burners, such as those adapted to burn different fuels, or to burn the same fuel in different ways, have existed. Examples of these are Reichhelm U.S. Pat. No. 3,308,868 and French Pat. No. 1,406,040.
In burners being used for gasifying fuel by mixing oil with hot products of combustion, such as that shown in Reichhelm U.S. Pat. No. 3,361,183, the gasification of the fuel is shown taking place in a separate chamber. This chamber has hot products of combustion entering the chamber at one inlet, liquid fuel entering it at another, and a mixture of the two being drawn out at an outlet port after gasification. It then goes into a mixing chamber for mixing with compressed air and into a burning chamber for burning. This structure, having a gasification chamber, can preheat for starting for the use of an electric heater around the gasification chamber. The structure, however, also results in undesirable thermal stresses due to the fact that the hot combustion gases must pass from the burning chamber to the gasification chamber. This method of preheat also takes a relatively long start-up time.